This project is jointly funded by the Electronic and Photonic Materials Program (EPM) in the Division of Materials Research (DMR) and the Electronics, Photonics, and Magnetic Devices Program (EPMD) in the Division of Electrical, Communications and Cyber Systems (ECCS).
goal of this project is to develop high-quality graphene samples on nanoscale gratings for the generation of terahertz (THz) light based on novel radiation mechanisms that so far have been the primary domain of high-energy electron beams in vacuum-based systems. Specifically, the mechanisms under study include a radically new cyclotron-like emission process, where angular motion is obtained via geometrical constraints rather than through the application of an external magnetic field, and the Smith-Purcell effect. The project activities involve a combination of nanolithography for the fabrication of highly sinusoidal nanoscale gratings, graphene synthesis via exfoliation and high-vacuum chemical vapor deposition, graphene transfer, and sample characterization via gated electrical studies, Raman spectroscopy, and THz-radiation measurements. The distinctive properties of graphene (including its linear energy dispersion, high electron velocity and mobility, and two-dimensional nature) are uniquely suited to the radiation mechanisms under study. At the same time, critical information about the underlying materials physics can be unveiled through the demonstration and investigation of these phenomena.
Non-technical Description: Graphene is a two-dimensional crystal consisting of a single layer of carbon atoms arranged in a honeycomb lattice. By virtue of several unique electronic, optical, and mechanical properties, it represents a promising materials platform to enable the continued evolution of electronic and photonic technologies towards ever increasing performance, miniaturization, and functionalities, well beyond the fundamental limits of traditional semiconductors. This project investigates the use of these properties to develop a new paradigm for THz light emission in compact solid-state systems. As a result, it may open the way for a new class of THz devices (including THz lasers potentially capable of room-temperature operation, unlike all existing semiconductor-based solutions), as needed for a wide range of emerging applications in security screening, medical diagnostics, and manufacturing quality control. In the course of these activities, education is promoted through the training of students in several areas of materials science and nanotechnology, with a strong emphasis on the involvement of undergraduates and high-school interns in addition to Ph.D. candidates. A related goal is the development of experimental modules based on the research methods and outcomes, to enhance the laboratory component of an undergraduate course on nanotechnology at Boston University (BU), and for demonstrations at local high schools (including institutes with large minority populations) by undergraduates engaged in BU Inspiration-Ambassadors program.
